ES2726031T3 - Aqueous radiation curable polyurethane compositions - Google Patents

Abstract

An aqueous radiation curable composition comprising - at least one (meth) acrylated polyurethane prepolymer (A) obtained from the reaction of: - at least one polyisocyanate compound (i), - at least one polyol (ii), - al less one hydrophilic compound (iii) containing at least one reactive group capable of reacting with isocyanate groups and capable of rendering the polyurethane prepolymer dispersible in aqueous medium, directly or after reaction with a neutralizing agent, to provide a salt , - at least one (meth) acrylated compound (iv) containing at least two reactive groups capable of reacting with isocyanate groups, - at least one (meth) acrylated compound (v) essentially containing one reactive group capable of reacting with groups isocyanate selected from among poly (meth) acryloyl monohydroxy compounds, and - optionally, at least one ethylenically unsaturated compound (B), wherein said composition comprises a total amount of (meth) acryl groups Polymerizable and optionally ethylenically unsaturated compounds of at least 3 meq per g total weight of (i), (ii), (iii), (iv), (v), and (B) as half by nuclear magnetic resonance spectroscopy 1 HOUR.

Description

DESCRIPTION

Aqueous radiation curable polyurethane compositions

The invention relates to radiation curable aqueous polyurethane compositions especially suitable for manufacturing scratch resistant coatings.

It has long been known that radiation curable polyurethane dispersions provide coatings for different substrates, such as wood, plastics and metal, which show good mechanical and chemical resistance, as well as some flexibility.

The ethylenically unsaturated polyurethanes have been manufactured from the chain extension of ethylenically unsaturated polyurethane prepolymers terminated in isocyanate with polyamines. The resulting polymers generally have a high molecular weight and contain hard urea segments that normally result in dispersions with a minimum high film formation temperature and, therefore, require the use of coalescing additives. Ethylenically unsaturated polyurethanes can also be manufactured from the end protection of an isocyanate terminated polyurethane prepolymer with an ethylenically unsaturated monomer, especially (meth) acrylated.

A disadvantage of these known radiation curable compositions is their limitation to provide high reactivity, which makes them less suitable for applications where high speed cure or low energy consumption is required. They are also less suitable for manufacturing pigmented coatings in which the presence of pigments reduces the penetration of UV light and limits a good curing in the inner mass. These compositions generally do not allow to obtain coatings that have a final hardness, scratch resistance and resistance to high stains.

Now, we have found radiation-curable polyurethane dispersions that remedy these problems.

Therefore, the present invention relates to a radiation curable aqueous composition comprising

- at least one prepolymer of (meth) acrylated polyurethane (A) obtained from the reaction of at least one isocyanate compound (i), at least one polyol (ii), at least one hydrophilic compound (iii) containing the less a reactive group capable of reacting with isocyanate groups and which is capable of returning the dispersible polyurethane prepolymer in aqueous medium, directly or after the reaction with a neutralizing agent, to provide a salt, at least one (meth) acrylated compound ( iv) containing at least two reactive groups capable of reacting with isocyanate groups, at least one (meth) acrylated compound (v) essentially containing a reactive group capable of reacting with isocyanate groups selected from monohydroxylated poly (meth) acryloyl compounds ; Y

- optionally, at least one ethylenically unsaturated compound (B), wherein said composition comprises a total amount of (meth) acrylated groups and, optionally, polymerizable ethylenically unsaturated groups of at least 3 meq per total weight in g of (i), ( ii), (iii), (iv), (v) and (B).

By ethylenically unsaturated polymerizable groups it is intended in the present invention to designate carbon-carbon double bonds which, under the influence of irradiation and / or a (photo) initiator, may undergo radical polymerization. The polymerizable ethylenically unsaturated groups are generally chosen from (meth) acrylic and allyl groups, preferably (meth) acrylic groups, most preferably acrylic groups. In the present invention, the term "(meth) acryl" should be understood to encompass acryl and methacryl compounds or derivatives, as well as mixtures thereof.

The compositions according to the invention are characterized by a level of (meth) acrylated groups and, optionally, high polymerizable ethylenically unsaturated; they contain at least 3 meq of (meth) acrylated and, optionally, ethylenically unsaturated groups polymerizable per total weight in g of the compounds (i), (ii), (iii), (iv), (v) and (B). The amount of (meth) acrylated and ethylenically unsaturated groups is usually measured by nuclear magnetic resonance spectroscopy and expressed in meq per g of solid material. A sample of the composition is dried for 1 day at room temperature and 12 h at 60 ° C and then dissolved in N-methylpyrolidinone. The sample is subjected to 1 H NMR analysis to measure the molar concentration of (meth) acrylated and ethylenically unsaturated groups using 1,3,5-bromobenzene as internal standard. The comparison between the peak assigned to the aromatic protons of the internal standard and the peaks assigned to the (meth) acrylated and ethylenically unsaturated double bonds makes it possible to calculate the molar concentration of (meth) acrylated and ethylenically unsaturated groups according to the formula (A x B) / C, where A is the integration of 1H of double bonds provided by the sample, B is the number of moles of the internal standard in the sample and C is the integration of 1H provided by the internal standard. Alternatively, the amount of (meth) acrylated and ethylenically unsaturated groups can also be measured by a titration method after the addition of an excess of pyridinium dibromide sulfate over said unsaturated groups (in glacial acetic acid as solvent and mercury acetate as catalyst). Said excess releases iodine in the presence of potassium iodide and the iodine is then titrated with sodium thiosulfate.

Preferably the total amount of polymerizable (meth) acrylated and ethylenically unsaturated groups is at minus 3.5 meq, especially at least 4 meq of polymerizable (meth) acrylated and ethylenically unsaturated groups per total weight in g of compounds (i), (ii), (iii), (iv), (v) and ( B).

Preferably, the total amount of polymerizable (meth) acrylated and ethylenically unsaturated groups does not exceed 10 meq of polymerizable (meth) acrylated and ethylenically unsaturated groups per total weight in g of the compounds (i), (ii), (iii), (iv), (v) and (B).

The radiation curable composition is preferably obtained by a method comprising

- a first stage comprising the reaction of the compounds (i), (ii), (iii) and (iv),

- a second stage, comprising the reaction of the product of the first stage with a compound (v) such that a prepolymer of polyurethane (meth) acrylated with protected ends is obtained,

- the dispersion in an aqueous medium of said acrylated polyurethane (meth) prepolymer with protected ends obtained after the second stage,

- an optional step comprising the reaction with a neutralizing agent to convert the hydrophilic groups provided by the compound (iii) into anionic salts,

- an optional stage in which the acrylated polyurethane (meth) prepolymer obtained after the second stage is reacted with a chain extender (vii),

- optionally the addition of an ethylenically unsaturated compound (B).

This procedure can be carried out by reacting a stoichiometric excess of compound (i) with compounds (ii), (iii) and (iv), preferably under substantially anhydrous conditions and at a temperature between 30 ° C and 130 ° C, more preferably between 70 ° C and 100 ° C, until the reaction between the isocyanate groups and the isocyanate reactive groups is substantially complete. The isocyanate content can be controlled by titration with an amine. The reactants are generally used in proportions corresponding to an equivalent ratio of isocyanate groups provided by the compound (i) to isocyanate reactive groups provided by the compounds (ii), (iii) and (iv) of 1.1 : 1 to 2: 1, preferably 1.4: 1 to 1.8: 1. The reaction can be facilitated by the addition of 5 to 40%, preferably 15 to 25%, by weight of a solvent to reduce the viscosity of the prepolymer. The solvent is preferably acetone or methyl ethyl ketone. During this procedure, it is usual to use catalysts to accelerate the reaction of the isocyanates to hydroxyls and to use inhibitors to avoid the radical reaction of the reactive unsaturations. Within the framework of this invention it is possible to use a sequential process during which the compound (i) and / or the compounds (ii), (iii) and / or (iv) are gradually added in two or more portions, or with a continuous feeding This is done to have better control over the exothermicity of the reaction, especially when no solvent is present.

Compounds (ii), (iii) and (iv) are preferably used in a molar ratio (ii) :( iii) :( iv) of 1: 1: 1 to 1:10:10, more preferably 1: 1 : 1 to 1: 5: 5.

At a later stage, the isocyanate terminated polyurethane prepolymer is reacted with the compound (v), preferably under the same conditions as the previous stage. The reactants are generally used in proportions corresponding to a ratio of equivalents of isocyanate groups provided by the prepolymer obtained in the first stage to isocyanate reactive groups provided by compound (v) of 2: 1 to 1: 1, preferably from 1.7: 1 to 1.25: 1. The isocyanate content can be controlled by titration with an amine.

In general, the prepolymer obtained after the reaction of (i), (ii), (iii), (iv) and (v) is dispersed in an aqueous medium by slowly adding the prepolymer to water or, conversely, adding water to the prepolymer Normally, this dispersion takes place under high shear mixing. Normally, the dispersion requires preliminary neutralization of the hydrophilic groups provided by the compound (iii), such as the carboxylic acid or sulfonic acid groups, to anionic salts. This is generally done by adding an organic or inorganic neutralizing agent to the prepolymer or water. Suitable neutralizing agents include ammonia, volatile organic tertiary amines, such as trimethylamine, triethylamine, triisopropylamine, tributylamine, N, N-dimethylcyclohexylamine, N, N-dimethylaniline, N-methylmorpholine, N-methylpiperazine, N-methylpyrrolidine and N-methylpyrrolidine and non-volatile inorganic bases comprising monovalent metal cations, preferably alkali metals such as lithium, sodium and potassium, and anions such as hydroxides, hydrides, carbonates and bicarbonates. Triethylamine and sodium hydroxide are preferred.

The total amount of these neutralizing agents can be calculated according to the total amount of acid groups to be neutralized. Generally, a stoichiometric ratio of 1: 1 is used. In general, the relative amounts of the compounds (i), (ii), (iii), (iv) and (v) are such that a stoichiometric excess of the compound (i) is used with respect to the compounds (ii), (iii), (iv) and (v) in such a way that a fraction of an isocyanate (meth) acrylated polyurethane prepolymer is obtained, that is, a prepolymer that still comprises some residual isocyanate groups. This isocyanate functional prepolymer fraction can then be subjected to extension. chain with a chain extender containing active hydrogen in the aqueous phase, generally at a temperature between 5 and 90 ° C, preferably 15 to 30 ° C. Water can act as a chain extender. Optionally, an additional compound (vii) comprising active amino groups capable of performing a chain extension of the remaining isocyanate end groups of the prepolymer is added. The chain extender is conveniently an aliphatic, alicyclic, aromatic or heterocyclic primary or secondary polyamine or hydrazine soluble in water having up to 60, preferably up to 12, carbon atoms. The total amount of compound (vii) used is generally calculated based on the amount of residual isocyanate groups present in the polyurethane prepolymer. The ratio in equivalents of isocyanate groups in the prepolymer to amine groups in the chain extender (vii) during the chain extension is generally in the range of 1: 0.7 to 1: 1, preferably 1: 0.9 to 1: 1. This ratio is more preferably 1: 1 to obtain a fully reacted polyurethane polymer, without residual free isocyanate groups.

The polyamine used preferably has an average functionality of 2 to 4, more preferably 2 to 3. Examples of such chain extenders (vii) useful herein include hydrazine, ethylenediamine, piperazine, 1,4-butanediamine, 1, 6-hexanediamine, 1,8-octanediamine, 1,10-decanediamine, 1,12-dodecanediamine, 2-methylpentamethylenediamine, triethylenetriamine, isophorondiamine (or 1-amino-3-aminomethyl-3,5,5-trimethicyclohexane), bis ( 4-aminocyclohexyl) methane, bis (4-amino-3-methicyclohexyl) methane, polyethyleneamines, polyoxyethyleneamines and polyoxypropyleneamines (e.g., TEXACO Jeffamines), as well as mixtures thereof.

Preferably, no chain extender compound (vii) is used.

In general, after the formation of the dispersion of the prepolymer and when it contains a volatile solvent with a boiling point below 100 ° C, the polymer dispersion is distilled. This is normally done at reduced pressure and at a temperature between 20 and 90 ° C, preferably 40 to 60 ° C.

By polyisocyanate compound (i) it is intended to designate any organic compound comprising at least two isocyanate groups. The polyisocyanate compound typically comprises a maximum of three isocyanate groups. Most preferably, the polyisocyanate compound (i) is a diisocyanate.

The polyisocyanate compound is generally selected from among aliphatic, cycloaliphatic, aromatic and / or heterocyclic polyisocyanates or combinations thereof.

Examples of aliphatic and cycloaliphatic polyisocyanates are 1,6-diisocyanatohexane (HDI), 1,1'-methylene bis [4-isocyanoccyclohexane] (H12MDI), 5-isocyanate-1-isocyanatomethyl-1,3,3-trimethylcyclohexane (diisocyanate Isophorone, IPDI). Aliphatic polyisocyanates containing more than two isocyanate groups are, for example, those derived from the aforementioned diisocyanates such as 1,6-diisocyanatohexane biuret and isocyanurate.

Examples of aromatic polyisocyanates are 1,4-diisocyanatobenzene (BDI), 2,4-diisocyanatotoluene (TDI), 1,1'-methylenebis [4-isocyanatobenzene] (MDI), xylylene diisocyanate (XDI), tetramethylxylene diisocyanate (TMXDI) , 1,5-naphthalene diisocyanate (NDI), tolidine diisocyanate (TODI) and p-phenylene diisocyanate (PPDI). The polyisocyanate (i) is preferably selected from aliphatic and cycloaliphatic polyisocyanates, more preferably diisocyanates. 1,1'-methylene bis [4-isocyanoccyclohexane] is especially preferred.

The amount of polyisocyanate compound (i) used for synthesis of the polyurethane prepolymer (A) is generally in the range of 10 to 60% by weight of the polyurethane prepolymer (A), preferably 20 to 50% by weight and more preferably from 30 to 40% by weight. By polyol (ii) it is intended to designate a polyol comprising at least two hydroxyl groups. The polyol (ii) may be selected from high molecular weight polyols having a number average molecular weight of at least 400, low molecular weight polyols having a number average molecular weight less than 400 or any mixture thereof. The high molecular weight polyol (ii) preferably has a number average molecular weight that does not exceed 5000, preferably not 2000, more preferably not 1000.

Examples of such high molecular weight polyols are polyester polyols, polyether polyols, polycarbonate polyols, fatty dimer diols, polybutadiene polyols, silicone polyols and polyacrylate polyols, as well as combinations thereof.

Suitable polyether polyols comprise polyethylene glycols, polypropylene glycols and polytetramethylene glycols, or block copolymers thereof.

Suitable polycarbonate polyols include the reaction products of diols such as ethylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol , dipropylene glycol, tripropylene glycol or tetraethylene glycol with phosgene, with dialkyl carbonates such as dimethyl carbonate, with diaryl carbonates such as diphenylcarbonate or with cyclic carbonates such as ethylene carbonate and / or propylene.

Suitable fatty dimer diols are obtained from the hydrogenation of dimer acids, preferably those comprising 36 carbon atoms.

Suitable polyacrylate polyols include those prepared by radical polymerization of (meth) acrylic and / or (meth) acrylamide monomers initiated by a thermal radical initiator in the presence of a hydroxylated mercaptan and followed by transesterification of the terminal group with a chain diol short, such as 1,4-butanediol.

Preferred are polyester, polyether and polycarbonate polyols.

Polyester polyols are particularly preferred, especially the hydroxyl-terminated reaction products of polyhydric alcohols, preferably dihydric, with polycarboxylic acids, preferably dicarboxylic acids, or their corresponding anhydrides, as well as those obtained from the polymerization by opening of lactone ring The polycarboxylic acids that can be used for the formation of these polyester polyols can be aliphatic, cycloaliphatic, aromatic and / or heterocyclic, and can be substituted, saturated or unsaturated. Examples of dicarboxylic acids are succinic acid, glutaric acid, adipic acid, subic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, hexahydrophthalic acid, isophthalic acid, terephthalic acid, ortho-italic acid, tetrachlorophthalic acid, 1,5-naphthalenedic acid , fumaric acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid, tetrahydrophthalic acid, trimellitic acid, trimesic acid and pyromellitic acid, or mixtures thereof. The polyester polyol may also contain an air drying component such as a long chain installed aliphatic acid, especially a fatty acid dimer. Polyhydric alcohols that are preferably used for the preparation of polyester polyols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol , neopentyl glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, dibutylene glycol, 2-methyl-1,3-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,4-cyclohexanedimethanol, ethylene oxide adducts or adducts of propylene oxide of bisphenol A or hydrogenated bisphenol A. Polyols such as glycerin, trimethylolethane, trimethylolpropane, dithrimethylolethane, di-trimethylolpropane and pentaerythritol can also be used.

Polyester polyols made from the polycondensation of neopentyl glycol and adipic acid and / or isophthalic acid are particularly preferred.

The total amount of polyol (ii) in the polyurethane prepolymer (A) is preferably 2 to 50% by weight of the polyurethane prepolymer (A), more preferably 3 to 30% by weight, most preferably 5 to 15 % in weigh.

Examples of low molecular weight polyols are ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, 1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol , 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 2-ethyl-1,6-hexanediol, cyclohexanedimethanol, trimethylolpropane, dithrimethylolpropane, glycerol, pentaerythritol and di-pentaerythritol.

According to a specific embodiment of the invention, a high molecular weight polyol is used in the preparation of the prepolymer (A).

According to another specific embodiment of the invention, a mixture of high molecular weight polyols and low molecular weight polyols is used.

The hydrophilic compound (iii) is generally a polyol comprising a functional group that may have an ionic or non-ionic hydrophilic nature. Preferably, it is a polyol containing one or more anionic saline groups, such as carboxylate and sulfonate saline groups, or acidic groups that can be converted into an anionic saline group, such as carboxylic acid groups or sulfonic acid groups. Preferred are hydroxycarboxylic acids represented by the general formula (HO) xR (COOH) and, where R represents a linear or branched hydrocarbon residue having 1 to 12 carbon atoms, and x and y are independently integers from 1 to 3. Examples of these hydroxycarboxylic acids include citric acid, malic acid, lactic acid and tartaric acid. The most preferred hydroxycarboxylic acids are a, a-dimethylolalcanoic acids, where x = 2 and y = 1 in the above general formula, such as, for example, 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid.

The amount of hydrophilic compound (iii) is generally 1 to 25% by weight of the polyurethane prepolymer (A), preferably 4 to 10% by weight.

By (meth) acrylated compound (iv) containing at least two reactive groups capable of reacting with isocyanate groups and at least one (meth) acrylated group it is intended in the present invention to designate any compound comprising at least one (meth) acrylated function, such as an acrylic or methacrylic group, and at least two nucleophilic functions capable of reacting with isocyanate, preferably hydroxyl functions.

Preferred are dihydroxylated (meth) acryloyl compounds and dihydroxylated poly (meth) acryloyl compounds.

Compounds (iv) comprising two hydroxyl functions and at least two (meth) acrylate functions are preferred. Acrylates are particularly preferred.

Particularly preferred compounds are those obtained from the reaction of diglycidyl compounds with (meth) acrylic acid.

Aliphatic diglycidyl compounds derived from alpha, omega diols having 4 to 12 carbon atoms or polyoxyalkylenediols, especially polyethylene glycol, polypropylene glycol or mixtures thereof containing oxyalkylene groups may be used. Preference is given, for example, to diglycidyl ether of 1,4-butanediol, diglycidyl ether of 1,6-hexanediol, diglycidyl ether of cyclohexanedimethanol, diglycidyl ether of polyethylene glycol, diglycidyl ether of polypropylene glycol, diglycidyl ether of hydrogenated diglycol A and of hydrogenated bisphenol F and its ethoxylated and / or propoxylated equivalents. It is also possible to use diglycidyl esters, such as diglycidyl hexahydrophthalate. The aromatic diglycidyl compounds derived from bisphenol A and bisphenol F are preferred. The diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F and their ethoxylated and / or propoxylated equivalents are particularly preferred. It is also possible to use diglycidyl esters, such as diglycidyl phthalate, N, N-diglycidylaniline, N, N-diglycidyl-4-glycidyloxyaniline. The diglycidyl ether diacrylate ester of bisphenol A is especially preferred.

Compounds (iv) obtained from the partial esterification of aliphatic or aromatic polyhydric polyols with (meth) acrylic acid and having an average residual hydroxyl functionality of at least 2.0 in the molecule can also be used. In this context, it is also possible to use the reaction products of such polyols with ethylene oxide and / or propylene oxide or mixtures thereof, or the reaction products of such polyols with lactones, which are added to these polyols in a ring opening reaction. Examples of suitable lactones are Y-butyrolactone and, in particular, 6-valerolactone and £ -caprolactone. Preferred are alkoxylated polyols having no more than two alkoxy groups with hydroxyl functionality and polyols modified with--caprolactone. Those skilled in the art know that the (meth) acrylation of polyols such as glycerol, trimethylolpropane, pentaerythritol, di-trimethylolpropane or di-pentaerythritol advances to a mixture of mono-, di-, tri-, tetra-, penta- and hexa (meth) acrylate and that a possible way to characterize the mixture is by measuring its hydroxyl value. Examples are glycerol mono- (meth) acrylate, trimethylolpropane mono- (meth) acrylate, pentaerythritol di- (meth) acrylate, dithrimethylolpropane di- (meth) acrylate, di- pentaerythritol tetra- (meth) acrylate and its polyethoxylated and / or polypropoxylated equivalents.

Compounds (iv) obtained from the hydrolysis of aliphatic, cycloaliphatic or aromatic compounds that carry an epoxy functionality together with at least one (meth) acrylic functionality can also be used. The products resulting from the hydrolysis of glycidyl (meth) acrylate, that is, 1,2-dihydroxy-3- (meth) acryloyl propane are particularly suitable. The amount of compound (iv) is generally 5 to 30% by weight of the polyurethane prepolymer (A), preferably 10 to 20% by weight.

By (meth) acrylated compound (v) which essentially contains a reactive group capable of reacting with isocyanate groups, it is intended in the present invention to designate any compound comprising at least one unsaturated function, such as an acrylic or methacrylic group, and a nucleophilic function capable of reacting with isocyanate, which is a hydroxyl group. Preferred are monohydroxy compounds of (meth) acryloyl, more particularly monohydroxy compounds of poly (meth) acryloyl. Acrylates are particularly preferred. Useful compounds (v) include the products of the esterification of aliphatic and / or aromatic polyols with (meth) acrylic acid having an average residual hydroxyl functionality of 1. Products of the partial esterification of the (meth) acrylic acid with tri-, tetra-, penta- or hexahydric polyols or mixtures thereof. In this context, it is also possible to use products of the reaction of such polyols with ethylene oxide and / or propylene oxide or mixtures thereof, or the products of the reaction of such polyols with lactones, which are added to these polyols in a ring opening reaction. Examples of suitable lactones are Y-butyrolactone and, in particular, 6-valerolactone and £ -caprolactone. These modified or unmodified polyols are partially esterified with acrylic acid, methacrylic acid or mixtures thereof until the desired residual hydroxyl functionality is achieved.

Other suitable compounds are (meth) acrylic esters with linear and branched polyols in which hidoxy functionality remains free, such as hydroxyalkyl (meth) acrylates having 1 to 20 carbon atoms in the alkyl group. Preferred molecules in this category are hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate. Compounds comprising at least two (meth) acryl functions, such as glycerol diacrylate, trimethylolpropane diacrylate, glycerol diacrylate, pentaerythritol triacrylate, dithrimethylolpropane triacrylate, dipentaerythritol pentaacrylate and their equivalent (polyx) ) propoxylates, are particularly preferred.

The amount of compound (v) is generally 10 to 60% by weight of the polyurethane prepolymer (A), preferably 30 to 50% by weight.

Preferably, the total amount of (meth) acrylated groups in the prepolymer (A) is at least 3.0 meq, especially at least 3.5 meq of acrylated (meth) groups per total weight in g of the compounds (i) , (ii), (iii), (iv) and (v).

Preferably, the total amount of (meth) acrylated groups does not exceed 10 meq of (meth) acrylated groups per total weight in g of the compounds (i), (ii), (iii), (iv) and (v). The composition according to the invention preferably comprises at least one ethylenically unsaturated compound (B), which is a compound comprising at least one unsaturated function such as an acrylic, methacrylic or allyl group, more particularly a compound containing (poly) (meth) acryloyl-. Acrylates are preferred.

The ethylenically unsaturated compound (B) may be selected from the (meth) acrylated (iv) and (v) compounds as described hereinbefore or it may be an ethylenically unsaturated compound that does not comprise any functionality that is capable of reacting with an isocyanate group.

The compound (B) is preferably selected from among the (meth) acrylated compounds (v) and from the ethylenically unsaturated compounds that do not comprise any functionality that is capable of reacting with an isocyanate group.

Aliphatic and aromatic polyhydric polyols that have been fully esterified with (meth) acrylic acid and do not substantially contain residual hydroxyl functionality in the molecule are particularly preferred. The products of the esterification of (meth) acrylic acid with tri-, tetra-, penta- and / or hexahydric polyols and mixtures thereof are suitable. In this context, it is also possible to use products of the reaction of such polyols with ethylene oxide and / or propylene oxide or mixtures thereof, or products of the reaction of such polyols with lactones, which are added to these polyols in a ring opening reaction. Examples of suitable lactones are Y-butyrolactone and, in particular, 8-valerolactone and £ -caprolactone. The compounds preferably used are alkoxylated polyols which have no more than two alkoxy groups with hydroxyl functionality and polyols modified with--caprolactone. These modified or unmodified polyols are preferably fully esterified with acrylic acid, methacrylic acid or mixtures thereof until no residual hydroxyl functionalities remain. Examples of polyunsaturated compounds of this category are trimethylolpropane triacrylate, glycerol triacrylate, tetraacrylate, pentaerythritol tetraacrylate, di-trimethylolpropane hexaacrylate di-pentaerythritol and their equivalents (poly) ethoxylated and / or (poly) propoxylated, and mixtures thereof.

It is also possible to use any compound from the category of urethane (meth) acrylates, epoxy (meth) acrylates, polyester (meth) acrylates and (meth) acryl (meth) acrylates or mixtures thereof.

The compound (B) can also be an ethylenically unsaturated compound that carries one or more additional functional groups or side chains that provide additional properties to the polymer. Ethylenically unsaturated siliconized and / or fluorinated compounds such as products marketed under the names IRR 154 and ADDITOL® HGX83 are particularly suitable.

The amount of ethylenically unsaturated compound (B) used is generally between 5 and 50% by weight, preferably between 20 and 30% by weight, of compound (B) with respect to the total amount of prepolymer (A) .

The present invention also relates to a process for the preparation of radiation curable compositions as described hereinbefore, said process comprising

- a first stage comprising the reaction of the compounds (i), (ii), (iii) and (iv),

- a second stage, comprising the reaction of the product of the first stage with a compound (v) such that a prepolymer of polyurethane (meth) acrylated with protected ends is obtained,

- the dispersion in an aqueous medium of said acrylated polyurethane (meth) prepolymer with protected ends obtained after the second stage,

- an optional step comprising the reaction with a neutralizing agent in order to convert the hydrophilic groups provided by the compound (iii) into anionic salts,

- an optional stage in which the acrylated polyurethane (meth) prepolymer obtained after the second stage is reacted with a chain extender (vii),

- an optional step comprising the addition of an ethylenically unsaturated compound (B).

If a chain extender (vii) is used, it is preferably added during, or after, the dispersion of the acrylated polyurethane (meth) prepolymer with protected ends in an aqueous medium.

The addition of ethylenically unsaturated compound (B) can be done after the second stage of the reaction. When the ethylenically unsaturated compound (B) is a compound that does not comprise functional groups that are capable of reacting with isocyanate groups, the compound may be added before, or during, the second stage of the reaction. According to a preferred embodiment of the invention, the compound (B) is added to the reaction mixture together with the compound (v).

According to another preferred embodiment of the invention, part of the compound (B) is added to the reaction mixture together with the compound (v) and another part of the compound (B) is added to the reaction mixture after the second stage. In this case, the same or different compounds (B) can be used.

In addition to the compound (B), or in substitution of the compound (B), compounds (C) which are not ethylenically unsaturated can also be added before, during or after the second stage of the reaction. These compounds (C) are preferably selected from silicone and / or hydroxylated polyacrylates such as Silclean® 3700. The amount of compound (C) is generally between 0 and 30% by weight, preferably between 0 and 10% by weight of compound (C) with respect to the total amount of prepolymer (A) and, optionally compound (B). The composition and process according to the present invention are advantageous because they are capable of providing dispersions with a low volatile organic compound (VOC) content, a high solids content, a Low viscosity, small particle size, excellent stability and low film formation temperature. Since the “environmentally friendly” aspect of a product is currently becoming an added value in the market, the elimination of solvents is reducing the content of volatile organic compounds (VOCs) and the suppression of amines reduces the perception of smell in the lining area and also possible post-health damage. The reduction of skin and eye irritations improves the safety in handling the product and does not impose the use of special labeling (Xi), which makes the product more attractive to the user.

The aqueous dispersions of the invention generally have a total solids content of 30 to 50% by weight, preferably 35 to 40%; a viscosity measured at 25 ° C of 20 to 5000 mPa.s, preferably 25 to 200 mPa.s, a pH value of 7 to 11, preferably 7 to 8.5, an average particle size of 10 to 1000 nm, preferably 50 to 150 nm. The film forming temperature preferably ranges from 0 to 20 ° C, more preferably from 0 to 5 ° C.

The compositions according to the present invention are capable of providing coatings that do not have tackiness even before radiation curing.

The radiation curable compositions according to the present invention are preferably curable by ultraviolet irradiation, generally in the presence of a photoinitiator. They can also be cured by electron beam irradiation, which allows the use of photoinitiator-free compositions. The compositions according to the invention provide extremely fast cure.

The compositions according to the invention show a higher reactivity, which allows curing at higher line speeds or with less radiative energy and higher productivity.

The compositions according to the invention make it possible to obtain coatings that after radiation curing show excellent chemical resistance against water, solvents and stains, superior mechanical resistance against scratching and abrasion - while remaining relatively flexible at room temperature or low. These coatings also have good adhesion on porous and non-porous substrates. The optical properties are responsible for its good transparency and high brightness.

The coatings obtained from the compositions according to the invention result in selective mechanical properties (harder and softer) and polarity of the polymer (more hydrophilic or hydrophobic) that allow to cover many different application areas such as wood coatings , plastic, glass, metal and concrete. The compositions according to the invention are also suitable for manufacturing inks and overprint varnishes. The present invention, therefore, also relates to the use of the compositions for manufacturing inks, varnishes or coatings and to a process for manufacturing inks, varnishes or coatings where a composition is used as described herein. The present invention also relates to a process for preparing a coated article comprising a step in which the article is coated with a radiation curable composition according to the invention.

The compositions according to the invention are particularly suitable for manufacturing wood furniture coverings and plastic resilient floor coverings. The compositions according to the invention are also particularly suitable for coating plastic articles, especially three-dimensional objects made from polyethylene, polypropylene, polycarbonate, optionally pre-coated with other coatings such as polyurethanes.

The compositions according to the invention, therefore, may also contain different additives such as biocides, stabilizers, thickeners, coalescing agents, antifoaming agents, wetting agents, wax and fillers.

The following examples illustrate the invention without limiting it.

Example 1:

A double-walled glass reactor, equipped with a magnetic stirrer, a thermocouple, a steam condenser and an addition funnel, was loaded with 45.3 g of a polyester polyol having an average molecular weight of 670, a number of 167 mg KOH / g hydroxyl obtained from the polycondensation of neopentyl glycol and a mixture of adipic acid and isophthalic acid in a 1: 1 weight ratio, 109.2 g of the adduct of acrylic acid and diglycidyl ether of bisphenol A (BpAAA), 34.3 g of dimethylolpropionic acid (DMPA), 231.3 g of 1,1'-methylene bis (4-isocyanoccyclohexane) (H12MDI), 279 g of acetone, 3.1 g of TINUVIN®622 and 0.6 g of butyltin laurate in the form of a 10% solution in acetone. The reaction mixture was heated to 60 ° C with stirring and maintained at reflux until the isocyanate content reached a value of 1.09 meg / g. Then, 0.4 g of 4-methoxyphenol dissolved in 207.1 g of DTMPTA, a product comprising a mixture of dithrimethylolpropane triacrylate and dithrimethylolpropane tetraacrylate and having a hydroxyl number of 137 mg of, was then slowly added to the reactor KOH / g, and the reaction mixture was refluxed until the isocyanate content reached a value of 0.19 meq / g. Next, 209 g of EBECRYL® 1290, a hexafunctional aliphatic urethane acrylate, was added to the reaction mixture and stirred until a homogeneous mixture was obtained. This mixture was then cooled to 45 ° C and 25.8 g of triethylamine was added with stirring. The resulting mixture was added slowly then to 1268 g of water at room temperature with high shear agitation until a stable dispersion was obtained. The acetone was distilled under vacuum at a temperature of 50 ° C until its level, as measured by gas chromatography, was below 0.15%. The polymer dispersion was then cooled below 30 ° C and 2.3 g of biocide (Acticide®MBS) was added. The dispersion was filtered on a 100 p screen and its dry extract was adjusted to 40% by adding water. The dry matter content was measured by a gravimetric method.

The viscosity of the dispersion was 33 mPa.s (measured at 25 ° C with a Brookfield RVT viscometer using a # 1 spindle at 50 rpm).

The average particle size of the aqueous polymer dispersion was 94 nm (measured by laser light scattering using an automatic Malvern particle size analyzer).

The granule content (grits) of the dispersion, that is, the amount of residue of the polymer dispersion filtered on a 50 pm sieve, was less than 100 mg / liter.

The minimum film formation temperature (TMFP) of the dispersion measured on a gradient heated metal plate was 0 ° C.

Colloidal stability was evaluated by observing the decantation and / or phase separation in a 200 g sample placed in an oven at 60 ° C; This was more than 10 days before the observable deterioration of the product. The dispersion properties are presented in Table 2 below.

The composition was then formulated with 1.5% photoinitiator (Additol® BCPK) and the viscosity was adjusted to 1500 mPa.s (Brookfield) using Additol®VXW 6360: water (1: 1) to a maximum of 2% , and its reactivity, scratch resistance, stain resistance, hardness, flexibility and adhesion were evaluated as specified below.

Reactivity: The method covers the minimum UV dose that is necessary to completely crosslink a 36p coating applied wet to a non-porous substrate (white paper, Silico Ultraflat). The coating was dried for 1 minute at 120 ° C and then cured under a UV lamp (Hg) of 80 W / cm at different conveyor speeds. The minimum dose is defined by the speed of the conveyor (m / min) that allows a solvent resistance greater than or equal to 50 double rubs with acetone. Rubs are made with a peace of cotton cloth saturated with acetone; a double rub equals a forward and backward travel on the coated surface. The number described is the number of double rubs required to break the coating.

Scratch resistance: The method covers the scratch resistance of a 36p coating applied wet to a non-porous substrate (white paper, Silico Ultraflat). The coating was dried for 10 minutes at 35 ° C and then cured twice under an 80 W / cm UV lamp (Hg) at a speed of 5 m / min. Scratching was evaluated at room temperature using a piece of steel wool fixed on an 800 g hammer and rubbed on the coated surface with a forward and backward motion. The number described is the number of simple rubs required to damage the surface and cause a visible loss of gloss due to abrasion.

Stain resistance: The method covers the chemical resistance of a 36 p wet coating applied to a non-porous substrate (5 mm thick white PVC). The coating was dried for 1 minute at 120 ° C and then cured under a UV lamp (Hg) of 80 W / cm at a speed of 5 m / min. The resistance was evaluated by placing a test substance on the coating, which is covered with a glass cover slip and left for 4 hours. The test substances are tear, black polish, black alcohol marker, BB750 dye in water, SR380 dye in turpentine and SG146 dye in turpentine. The spots were washed with a couple of rubs using a tissue paper saturated with isopropanol. The remaining spots were evaluated visually using a scale of 1-5, 5 = the best result. A high value (5) is expected to provide the best protection against any spillage of household products.

Hardness: The method covers the surface hardness of a 120 p coating applied wet to glass. The coating was dried for 5 minutes at 40 ° C and then 5 minutes at 80 ° C and finally cured 3 times under a UV lamp (Hg) of 80 W / cm at a speed depending on the reactivity. The coated samples were stabilized for 24 hours in a conditioned room (20 ° C, 50% humidity) and the hardness was determined with a pendulum test (Persoz) in seconds on 3 surface positions. The average value was calculated.

Scratch hardness with pencil: Scratch hardness with pencil (ASTM D-3363). The method covers the hardness of a 36 p coating applied wet to polycarbonate sheets. It is used in industry to determine the scratch hardness of coatings. The coating was dried for 10 minutes at 40 ° C and cured twice under a UV lamp (Hg) of 80 W / cm at a rate of 2 times 5 m / min. The coated samples are stabilized for 24 hours in a conditioned room (20 ° C, 50% humidity). The pencil scratch hardness was determined by scratching the surface of the coating with the pencils using a given force and with a given angle. The hardness was rated as softer to harder on a 2B-B-HB-F-H-2H-3H-4H-5H-6H scale. A high hardness level is desired to provide optimum mechanical protection of the coating.

Flexibility: The method covers the flexibility of a 36p coating applied wet to a non-porous substrate (White PVC 5 mm thick). The coating was dried for 1 minute at 120 ° C and then cured under a UV lamp (Hg) of 80 W / cm at a speed of 5 m / min. The flexibility of the coated PVC can be evaluated at room temperature after folding at 90 ° and then at 180 °. Defects (cracks, loss of adhesion) are recorded on a scale of 1-5, 5 = the best result. The attributions are 1 = serious defects at 90 °; 2 = moderate defects at 90 °; 3 = severe defects at 180 °; 4 = moderate defects at 180 °; 5 = no defects at 180 °. A high value (5) is expected not to generate problems in handling flexible substrates and is a prerequisite for good thermal and dimensional stability on rigid substrates.

Water macula: The method covers the water resistance of a 36p coating applied wet to a non-porous substrate (5 mm thick white PVC). The coating was dried for 1 minute at 120 ° C and then cured under a UV lamp (Hg) of 80 W / cm at 5 m / min. The resistance was evaluated by making cross sections on the surface coated with a knife and placing a drop of water in the middle for a period of 1 hour at room temperature. Water was removed using a dry tissue. Surface degradation was assessed visually to detect bleaching or degradation using a scale of 1-5.5 = the best result. A high value (5) is expected to provide the best protection against water spills.

Adhesion: The method covers the adhesion of a 36 p wet coating applied to a non-porous substrate (white PVC 5 mm thick). The coating was dried for 1 minute at 120 ° C and then cured under a UV lamp (Hg) of 80 W / cm at a speed of 5 m / min. 5 cuts of ~ 1 cm are made and separated by ~ 1 mm using a knife, followed by 5 similar cuts in the transverse direction. Adhesion was measured using an adhesive tape firmly pressed on the liner with cross cuts and removed quickly; Damage to the surface with cross sections of the coating due to loss of adhesion is expressed on a scale of 1-5, 5 = the best result. High adhesion (5) is necessary to ensure a strong permanent bond between the coating and the substrate.

The results obtained are represented in Table 3 below.

Examples 2 to 5, 7 to 16 and comparative example 6R:

In Examples 2 to 5 and 7 to 16, the procedure described in Example 1 was repeated, except that different amounts and different constituents were used, as specified in Table 1 below. Unless otherwise specified, the amounts of the different compounds are expressed in g.

In Examples 2 to 5, 6R and 7 to 16, hexafunctional urethane acrylate EB®1290 was omitted.

In Example 4, DPHA, a mixture of dipentaerythritol hydroxypentaacrylate and dipentaerythritol hexaacrylate, having a hydroxyl number of 67 mg KOH / g, was used instead of DTMPTA.

In Example 5, DPHA, a mixture of dipentaerythritol hydroxypentaacrylate and dipentaerythritol hexaacrylate, having a hydroxyl number of 67 mg KOH / g, was used instead of DTMPTA and DPHA was also used instead of EB® 1290.

In comparative example 6R, compound (iv) was not used: the adduct of acrylic acid and diglycidyl ether of bisphenol A (BPAAA) was replaced by 15.4 g of ethylene glycol.

In Example 7, PCDLT4691 (Asahi Kasei), a butanediol: hexanediol (9: 1) polycarbonate of average molecular weight of 1000 and having an average hydroxyl number of 110 mg of KOH / g, was used instead of the diol Of polyester.

In Example 8, dimethylolpropionic acid (DMPA) was replaced by dimethylolbutanoic acid (DMBA). Neutralization with triethylamine occurs stoichiometrically based on the moles of carboxylic acid.

In comparative example 9R, the polyether diol is stoichiometrically replaced by an excess of the adduct of acrylic acid and diglycidyl ether of bisphenol A (BPAAA).

In Example 10, the polyester polyol is replaced by 2-ethyl-2-butyl-1,3-propanediol.

In Example 11, the polyester polyol is stoichiometrically replaced by PRIPOL®2033 (Unichema), which is a fatty acid dimer diol composed of 36 carbon atoms and having an average molecular weight of ~ 600 Dalton and a hydroxyl value of 196-206 mg of KOH / g.

In Example 12, the diisocyanate (H12MDI) is replaced by a mixture of 199 g of H12MDI and 15.4 g of DESMODUR® N3300 (HDI isocyanurate) in a 95: 5 molar ratio.

In Example 13, neutralization was performed with 32.1 g of ammonia (110% molar compared to carboxylic acid) in the aqueous phase instead of triethylamine (100% molar compared to carboxylic acid) in the prepolymer.

In Example 14, 24.8 g of IRR154, which is a silicone oil based urethane acrylate, was added at a level of 5% with respect to the total weight of the prepolymer instead of EBECRYL® 1290.

^{In Example 15, 0.6 g of ADDITOL® HGX83, which is a fluorinated acrylate, was added at a level of 0.1} % ^with respect to the total weight of the prepolymer instead of EBECRYL® 1290.

In Example 16, 6.01 g of SILCLEAN® 3700 was added, which is a hydroxyl-functional polyacrylate modified with silicone of average molecular weight of 15,000 Dalton supplied in the form of a 25% solution in methoxypropyl acetate, at a level 7% with respect to the total weight of the prepolymer instead of EBECRYL® 1290.

The properties of the compositions are represented in Tables 2 and 3.

Table 3

The comparison of Examples 1 to 5 and 7 to 12 with Comparative Example 6R shows the best performance of the coatings obtained with the compositions according to the invention. Especially, the comparison of Example 2 with Comparative Example 6R obtained exactly with the same constituents, with the exception of compound (iv), shows the benefit of the compositions according to the invention.

Claims (17)

1. A radiation curable aqueous composition comprising - at least one prepolymer of (meth) acrylated polyurethane (A) obtained from the reaction of: - at least one polyisocyanate compound (i), - at least one polyol (ii), - at least one hydrophilic compound (iii) containing at least one reactive group capable of reacting with isocyanate groups and which is capable of returning the dispersible polyurethane prepolymer in aqueous medium, directly or after the reaction with a neutralizing agent, to provide a salt - at least one (meth) acrylated compound (iv) containing at least two reactive groups capable of reacting with isocyanate groups, - at least one (meth) acrylated compound (v) which essentially contains a reactive group capable of reacting with isocyanate groups selected from monohidoxylated poly (meth) acryloyl compounds, and - optionally, at least one ethylenically unsaturated compound (B), wherein said composition comprises a total amount of (meth) acrylated and, optionally, ethylenically unsaturated polymerizable groups of at least 3 meq per g of total weight of (i), (ii), (iii), (iv), (v) and (B) as measured by 1H nuclear magnetic resonance spectroscopy. 2. Radiation curable composition according to claim 1 wherein the composition comprises a total amount of (meth) acrylated groups and, optionally, polymerizable ethylenically unsaturated groups of at least 3.5, preferably at least 4 meq per g of total weight of ( i), (ii), (iii), (iv), (v) and (B) as measured by 1H nuclear magnetic resonance spectroscopy. 3. Radiation curable composition according to claim 1 or 2 wherein the prepolymer of (meth) acrylated polyurethane (A) comprises a total amount of (meth) acrylated groups of at least 3.0 meq of (meth) acrylated groups per g Total weight of compounds (i), (ii), (iii), (iv) and (v) as measured by 1H nuclear magnetic resonance spectroscopy. 4. Radiation curable composition according to any of the preceding claims obtained by a method comprising - a first stage comprising the reaction of the compounds (i), (ii), (iii) and (iv), - a second stage, comprising the reaction of the product of the first stage with a compound (v) in such a way that a prepolymer of (meth) acrylated polyurethane (A) with protected ends is obtained, - the dispersion in an aqueous medium of said prepolymer of (meth) acrylated polyurethane (A) with protected ends obtained after the second stage, - an optional step comprising the reaction with a neutralizing agent in order to convert the hydrophilic groups provided by the compound (iii) into anionic salts, - an optional stage in which the prepolymer of (meth) acrylated polyurethane (A) obtained after the second stage is reacted with a chain extender (vii), - optionally, the addition of an ethylenically unsaturated compound (B). 5. Radiation curable composition according to claim 4 wherein the composition comprises a total amount of (meth) acrylated groups and, optionally, polymerizable ethylenically unsaturated groups of at least 3.5, preferably at least 4 meq per g of total weight of ( i), (ii), (iii), (iv), (v) and (B) as measured by 1H nuclear magnetic resonance spectroscopy. 6. Radiation curable composition according to claim 4 or 5 wherein the prepolymer of (meth) acrylated polyurethane (A) comprises a total amount of (meth) acrylated groups of at least 3.0 meq of (meth) acrylated groups per g Total weight of compounds (i), (ii), (iii), (iv) and (v) as measured by 1H nuclear magnetic resonance spectroscopy. 7. Radiation curable composition according to any of the preceding claims wherein the polyol (ii) has a number average molecular weight of at least 400. 8. The radiation curable composition according to claim 7, wherein the polyol (ii) is a polyester polyol having a number average molecular weight of at least 400. 9. Radiation curable composition according to any of the preceding claims, wherein the polyisocyanate (i) is selected from aliphatic and cycloaliphatic polyisocyanates. 10. Radiation curable composition according to any of the preceding claims, wherein the hydrophilic compound (iii) is selected from hydroxycarboxylic acids represented by the general formula (HO) ^x R (COOH) ^and , wherein R represents a linear hydrocarbon residue or branched having 1 to 12 carbon atoms, yxey are independently whole numbers from 1 to 3. 11. Radiation curable composition according to any of the preceding claims, wherein the (meth) acrylated compound (iv) is selected from the products of the reaction of diglycidyl compounds with (meth) acrylic acid. 12. Radiation curable composition according to claim 11, wherein the (meth) acrylated compound (iv) is the diacrylate ester of diglycidyl ether of bisphenol A. 13. Radiation curable composition according to any of the preceding claims, wherein the (meth) acrylated compound (v) is selected from the products of the esterification of aliphatic and / or aromatic polyols with (meth) acrylic acid having a functionality average residual hydroxyl of about 1. 14. Radiation curable composition according to any of the preceding claims, comprising an ethylenically unsaturated compound (B) selected from the products of the esterification of (meth) acrylic acid with tri-, tetra-, penta- and / or hexahydric polyols and their mixtures. 15. Method for the preparation of a radiation curable composition according to any of the preceding claims comprising: - a first stage comprising the reaction of the compounds (i), (ii), (iii) and (iv), - a second stage, which comprises the reaction of the product of the first stage with a compound (v) in such a way that a prepolymer of (meth) acrylated polyurethane (A) with protected ends is obtained, - the dispersion in an aqueous medium of said prepolymer of (meth) acrylated polyurethane (A) with protected ends obtained after the second stage, - an optional step comprising the reaction with a neutralizing agent in order to convert the hydrophilic groups provided by the compound (iii) into anionic salts, - an optional stage in which the prepolymer of (meth) acrylated polyurethane (A) obtained after the second stage is reacted with a chain extender (vii), - an optional step comprising the addition of an ethylenically unsaturated compound (B). 16. The method according to the preceding claim, further comprising the step of adding a non-ethylenically unsaturated compound (C) selected from siliconized and / or hydroxylated polyacrylates, wherein said compound (C) is added before, during or after the second reaction stage. 17. Method for preparing a coated article comprising a step wherein the article is coated with a radiation curable composition according to any one of claims 1 to 14.